The present invention relates to an ensilage or forage harvester cutterhead, and more specifically relates to a cutterhead including a closed cylindrical drum having knife retainers fixed to its outer surface, with each knife retainer being in the form of an angular piece of material having a first leg that carries a knife and a second leg that extends from the drum to the area under the knife so as to form a paddle or impeller which serves to carry and discharge crop tangentially to the drum through the cutterhead housing discharge opening.
An example of a cutterhead of the above-mentioned type is disclosed in U.S. Pat. No. 4,061,284, granted 6 Dec., 1977. In this structure, sharp corners or pockets are defined between in the zone between circumferentially adjacent knife retainers. While DE-OS-1 507 278 discloses knife retainers having smooth curved surfaces and U.S. Pat. Nos. 2,450,507 and 4,011,998 respectively have knives and separate members that are curved and act as a crop impelling surfaces, these surfaces are subject to wear and are expensive and/or difficult to replace and/or difficult to construct.
The problem underlying the invention is seen in the fact that the impelling surfaces show wear after high volume production runs and that, in the case where the impelling surfaces are formed like those disclosed in the above-identified U.S. Pat. No. 4,061,284, wet crop that should be ejected is caked onto the impelling surfaces.